Using the 12-50mm on a Panasonic body is definitely not the first option that comes into mind. However, the multi-aspect-ratio sensor of GH1 (& GH2) really makes the difference for video when shooting wide angle. For reference, the FOV of 14mm 16:9 on GH1 roughly equals the FOV of 12mm 16:9 on E-PM1. Therefore, 12mm on GH1 /& GH2) 16:9 is truly wide! I don't know if others use this combination?

So, my answer is the 12mm wideangle for video. I also really much like the weight and the power zoom option of the 12-50mm.

P.S. I get slightly wider image by using manual zoom rather than power zoom. Is this normal?